Spoolless ribbon cartridge with lift and feed features combined

ABSTRACT

A spoolless ribbon cartridge containing either an endless fabric ribbon or a roll of single-pass carbon ribbon and having projecting members which hold a portion of ribbon accessible for printing. The cartridge has built-in rotatable drive members for forcing used ribbon into a chamber of the cartridge where it is stored in random, multi-folded fashion. By using loosely meshed gears as drive members, the ribbon does not stick to the drive members and may be precreased during entry into the chamber. The drive members are rotated under control of a ribbon lift mechanism, which positions the cartridge such that printing occurs alternately from the upper and lower halves of the ribbon. Such rotation may effect a half character movement of the ribbon in each printing cycle or a full character movement of the ribbon in every other print cycle, depending on the design.

United States Patent Perry et al.

LIFT AND FEED FEATURES COMBINED Assignee:

Filed:

Inventors: Donald S. Perry, Los Altos, Calif;

Wyland L. Fowler, Green; Richard E. Shattuck; Hans W. Mueller, both of Cortland, all of NY.

SCM Corporation, New York, NY.

Apr. 16, 1973 Appl. No.: 351,694

Related U.S. Application Data Division of Ser. No. 259,766, June 5, 1972.

U.S. Cl 197/151, 197/158, 197/168 Int. Cl B4lj 33/14 Field of Search 197/151, 157, 158, 159,

References Cited UNITED STATES PATENTS [451 Feb. 4, 1975 3,513,957 5/1970 Ricciardi et a1. 197/151 3,584,722 6/1971 Albrile 197/158 3,613,857 10/1971 Thevis et a1. 197/151 3,747,734 7/1973 Norman et a1 197/157 Primary ExaminerErnest T. Wright, Jr. Attorney, Agent, or FirmArmand G. Guibert; Milton M. Wolson; John A. Taylor [57] ABSTRACT.

A spoolless ribbon cartridge containing either an endless fabric ribbon or a roll of single-pass carbon ribbon and having projecting members which hold a portion of ribbon accessible for printing. The cartridge has built-in rotatable drive members for forcing used ribbon into a chamber of the cartridge where it is stored in random, multi-folded fashion. By using loosely meshed gears as drive members, the ribbon does not stick to the drive members and may be precreased during entry into the chamber. The drive members are rotated under control of a ribbon lift mechanism, which positions the cartridge such that printing occurs alternately from the upper and lower halves of the ribbon. Such rotation mayeffect a half character movement of the ribbon in each printing cycle or a full character movement of the ribbon in every other print cycle, depending on the design.

5 Claims, 5 Drawing Figures SPOOLLESS RIBBON CARTRIDGE WITH LIFT AND FEED FEATURES COMBINED CROSS-REFERENCE TO RELATED APPLICATION This is a division of application Ser. No. 259,766, filed June 5, 1972.

BACKGROUND OF THE INVENTION This invention relates to a ribbon mechanism for an office machine, such'as a typewriter, and more particularly, to a ribbon cartridge and a lift and feed mechanism therefor. I

Ribbon cartridges are known (from US. Pat. Nos. 2,902,136, 3,008,561, 3,151,724 3,260,344, and 3,356,202, for example), but these all have disadvantages-Most have a multiplicity of parts such as supply and take-up spools, and drive means for both. In most cases, cartridge insertion in the machine requires careful location and a steady hand to pass the ribbon between the forks of the usual ribbon vibrator, or worse, requires manual stripping of a portion of the ribbon for such purposes, thus involving messy contact between the ribbonand the operators hands. Furthermore, because of the varying level of the ribbon on the take-up spool, during the feed operation the load on the ribbon tends to increase to the point of breakage, again involving a handling of the ribbon with consequent soiling of the operators hands.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems by providing a ribbon cartridge which is very simple'in structure because it obviates the need for supply and take-up spools and their interrelated drives; eliminates need for a separate, variably positionable ribbon support mechanism; and incorporates a ribbon feed which stores the ribbon in the cartridge in random folds and may precrease it for more compact storage. The cartridge may contain inked ribbon, carbon ribbon, or the like and is readily interchangeable with similar cartridges. Spool herein refers to a flanged ribbon bobbin. By providing interfitting pivot members on each cartridge and ona support in the typewriter, an old cartridge can be lifted out of the support and a replacement cartridge dropped onto the latter with an easy, simple motion and pressed into position for printoperation controlled rocking of its supported ribbon to alternate upper and lower elevations as determined by a ribbon lift mechanism. Further, ribbon feed members are built into the cartridge and operated by a mechanism forming part of the ribbon lift mechanism.

Accordingly, it is an object of the invention to provide a spoolless prethreaded ribbon cartridge of simple structure, adaptable to use either an endless web fabric ribbon or a single-pass carbon ribbon.

It is another objct of the invention to provide a lowcost, throw-away type of cartridge for such ribbons requiring little skill for insertion and removal.

It is still another object of the invention to provide a ribbon cartridge in which the ribbon lift and ribbon feed mechanisms are combined.

BRIEF DESCRIPTION OF THE DRAWING The objects, features, and advantages of the invention will be apparent from a subsequent description of preferred embodiments of the invention made with reference to illustrations in the accompanying drawing, in which:

FIG. 1 is a perspective view of a fabric ribbon car tridge according to a first embodiment of the invention, including a lift and feed mechanism;

FIG. 2a is an enlarged perspective view of the ribbon feed entrance of the cartridge of FIG. 1, showing the ribbon disposed between dual feed gears with oscillating packing fingers for moving the entered ribbon away from the feed gears, while FIG. 2b is a plan view of same including a feed ratchet, pawl and detent;

FIG. 3 is a perspective view of a carbon ribbon cartridge according to a second embodiment of the invention, again including a lift and feed mechanism; and

FIG. 4 is an enlarged perspective view of the ribbon supply exit of the cartridges of FIG. 1 or FIG. 3, showing the integral ribbon guides within the cartridge housing.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to FIGS. 1 through 4, these show the typewriter ribbon supply and its lift and feed mechanism as particularly applied to a printing machine such as a typewriter having a single multi-character print element 42 movable laterally over the surface ofa record medium 14 supported on a laterally fixed platen 15, although the concept is equally applicable to typewriters having a laterally movable document carriage and multiple typebars. A fabric ribbon cartridge 1 in FIG. 1 is a first embodiment of the invention, and a carbon ribbon cartridge 61 in FIG. 3 is a second embodiment, each of the cartridges 1, 61 being interchangeably insertable in a support bracket 3 rigidly mounted on a support (not shown) for the print element 42 (shown in dotted outline) of the example, or forming part of the typewriter frame if applied to a typewriter having multiple typebars supported in a fixed segment of the typewriter frame. Cartridges 1 and 61 are each pivotable about pivot studs 4, 5 fixed to vertical side flanges 2b, 2a of support bracket 3. The studs 4, 5 enter notches 9 or 109 (only one shown in FIG. 1) formed in the sidewall 6 or 106 of each cartridge 1, 61 for purposes of ready insertion and removal by a simple drop-in/lift-out technique and for locating the ribbon 8 or 66 with respect to the platen 15. A latch (not shown) may lock the cartridge 1 or 61 down.

Fabric ribbon cartridge 1 is in the form of a roughly U-shaped housing enclosing a chamber 7. Sidewall 6 of cartridge 1 is of sufficient depth to permit chamber 7 to accommodate the vertically oriented ribbon 8. Similarly, the base 10 of chamber 7 is of sufficient area to accept a predetermined length of fabric ribbon 8. Two projecting members or parts 13a, 13b of cartridge 1 which form the arms of the U function as supports and guides for the active portion 8a of fabric ribbon 8. The spacing between portions 13a, 13b and their length is such as to accommodate the entry of print element 42 into printing position relative to the active ribbon portion 8a. In cartridge 1, fabric ribbon 8 is an endless web, supplied with and prethreaded in cartridge 1 so that during typing operation, ribbon 8 is pulled to the right (as shown by the arrow on portion 8a in FIG. 1)

through an exit gap 56 of cartridge 1 to present successive fresh surfaces of ribbon 8 as'the active ribbon portion 8a between the multi-character single print element 42 and the usual record medium 14 supported on a platen 15, the ribbon movement resulting from rotation of feed rotors in the form of feed gears 11 and 12, described in detail subsequently. Gears 11, 12 serve as the inlet to chamber 7 and their rotations stuff the recently used, now inactive section 8 b of ribbon 8 into chamber 7.

In addition to chamber 7, cartridge 1 contains within it fixed, integral exit guide pair members 45, 46 and 47, 48 (best seen in FIG. 4), oriented to insure smooth egress of ribbon 8 from cartridge 1 and to prevent previously entered sections 8b of ribbon 8 from being prematurely forced out of chamber 7. Guide pair members 47, 48 have a gap 56 between them equivalent to the thickness of ribbon 8, which gap 56 forms the exit of cartridge 1. The inner guide pair members 45, 46 are spaced slightly further apart than the exit guides 47, 48 so that the exiting portion of ribbon 8 is funneled from a multiple ribbon thickness at the entrance to guide members 45, 46 to a single ribbon thickness at guide members 47, 48 to insure proper egress.

As mentioned previously, after passage through exit gap 56 in the left projection 13b of cartridge 1, the active portion 8a of ribbon 8 passes between print element 42 and record medium 14 to the right projection 13a of cartridge 1, where it is subsequently picked up by the feed gears 11, 12. Ribbon 8 may be guided in this traverse by means of a pair of chutes 58a, b, (158a, lS8b in cartridge 61) a respective one of the pair forming part of sidewall 6 in the area of projections 13a, 13b. Chutes 58a, b may be provided with flanges 59 for better control, if desired (see FIG. 2a). Ribbon feed-in gear 11 (see FIG. 2b), fixed on a vertical shaft 55a, has two spaced eccentrics or grooves 49 in its periphery (for a purpose explained subsequently) and its teeth 170 mesh loosely with teeth 17b of a gear 12, fixed on a parallel shaft 55b, and identical to gear 11 except that gear 12 has an extra two teeth 17 b. The distance between the shafts 55a, 55b and the gear sizes is such that space 16 between gears 11, 12 is approximately the thickness of ribbon 8 so as to insure proper feeding of ribbon 8 between gears 11, 12 during the gear drive operation for re-entry of now inactive ribbon 8 into chamher 7. Fixed to shaft 55a is a drive ratchet 53, the teeth 50 of which cooperate with a feed pawl 38 to rotate feed gear 11 in the counterclockwise direction. Reentry of ribbon 8 into chamber 7 could be achieved with a pair of plain rollers (not shown), but ribbon 8 tends to stick to such rollers. The problem of sticking is solved by use of loosely-meshed gears ll, 12 as drive members and, furthermore, precreasing of ribbon 8 by action of teeth 17a, 17b provides better packing of ribbon 8 within chamber 7, as explained subsequently.

Maintenance of proper tension on the active portion 8a of ribbon 8 during print operation is assured by a resilient or spring member 57 (see FIG. 4 for best view) positioned near ribbon exit gap 56. Spring member 57 has a formed end 60 adjacent feed-out guide chute 58b and is fastened to sidewall 6 by rivets 62, or the like, the length of end 60 being such that spring 57 is under stress when fastened to sidewall 6. If cartridge 1 is plastic, spring 57 may be integrally molded. Ribbon 8, being inserted between the formed end 60 and guide chute 58b, is therefore clamped between the two and subject to friction force exerted by spring 57. Ribbon 8 is thus held substantially taut since on the other side, feed gears 11, 12 are locked against reverse rotation by interaction of a detent 63 and ratchet 53 on top of gear 11.

To facilitate the above-mentioned packing and to prevent ribbon 8 crowding in the area near the outlet of gears 11, 12, the pair of spaced grooves 49 (see FIG. 2a) may be made eccentric with respect to shaft 55a, similar grooves 49 on gear 12 being likewise eccentric with respect to shaft 55b (note that the upper portion of gear 11 has been removed in FIG. 2a for better visibility of the members next described). A pair of fingers 51a, 51b are each mounted in eccentric grooves 49 by means of their arcuate clasp members 52. A sliding fit between clasp members 52 and grooves 49 thus tends to oscillate members 51a, 51b not only together and apart, but also back and forth as eccentric grooves 49 rotate with shafts 55a, 55b. Friction between clasp members 52 and grooves 49 and/or the pressure of the entered ribbon portion 8b keeps ends 64 of fingers 51a, 51b in contact with the inside of sidewall 6 (not shown in FIG. 2a). In this fashion, as ribbon 8 is being creased and stuffed into chamber 7 during rotation of shaft 55a, fingers 51a, 51b projecting inwardly into chamber 7 serve to strip ribbon 8 from gears ll, 12 and oscillation of these fingers 51a, 51b pushes the creased ribbon 8 away from the area near gears 11, 12. It will be understood, of course, that the oscillation may be omitted, if desired, in which case though not illustrated grooves 49 may be made noneccentric and fingers 51a, 51b are then fixed barriers which only assist in stripping ribbon 8 from gears 11,12.

In a second embodiment, shown in FIG. 3, a similar cartridge 61 having external dimensions identical to those of cartridge 1 is partitioned into two chambers 65a, 65b, the first chamber 65a being of sufficient area to accept the used portion 66b of a carbon ribbon 66 from a spoolless" supply roll 67 which supplies the active portion 66a of the carbon ribbon 66. Roll 67, confined in the second chamber 65b, has a flangeless bobbin 67a and is rotatable around a pin 69 located in a slot 68. The purpose of slot 68 is to enable the operator to judge the amount of ribbon 66 remaining on roll 67 so that its exhaustion will not catch the operator unawares. The construction of the remainder of carbon ribbon cartridge 61 is identical to that of fabric ribbon cartridge 1 except that there is no need for communication between chambers 65a and 65b, since carbon ribbon 66 is nonreusable and travels past print element 42 only once. Accordingly, when the nonreusable carbon ribbon 66 on supply roll 67 is exhausted, cartridge 61 is discarded.

The drive means for lifting ribbon 8 and for feeding fresh ribbon 8 to print element 42 will next be described. As this mechanism is identical for both fabric ribbon cartridge 1 and carbon ribbon cartridge 61, the description will be made only with respect to cartridge 1 and with reference to FIG. 1 alone. As seen therein, a lift bellcrank 18 is rockably supported on pivot 5, bellcrank 18 being in the form of an inverted V with arms 19, 22. Arm 19 of bellcrank 18has an ear 40 formed into its upper margin (as seen in FIG. 1), ear 40 being of such length as to project under and give sup port to cartridge 1. Location of a similar ear 39 on the upper margin of arm 22 allows the previouslymentioned drop-in mode of insertion of cartridges 1 and 61, abutment of ear 39 with a second point under cartridge 1 providing the necessary alignment of notches 9 and pivots 4, 5. The other arm 22 of bellcrank 18 terminates in pivot disc 23 which is retained within a yoke 24 of an upward extension 25 ofa bail 26. Bail 26 is pivotally supported on a stud 27 mounted on the support (not shown) for print element 42 (or on a frame member in the case of a conventional type writer).

A lower extension 28 of bail 26 has a cam follower in the form of a cam roller 29 rotatably mounted at the free end of extension 28 (Le, remote from stud 27). Bail 26 is adapted to rock back and forth because cam roller 29 lies within the symmetrical, approximately elliptical path defined by a cam in the form ofa camming slot 30 cut into a face 31 of a gear 32. Gear 32 also mounted on the support for print element 42 is in mesh with a like-mounted actuating gear 33 driven by a power roll shaft 34 An axial slot 70 on the surface of shaft 34 and a mating tooth 71 on gear 33 provide lateral slidability of gear 33 on shaft 34 (only in the case of thesingle print element typewriter of the example, gear 33 being laterally fixed in the case of a conventional typewriter).

At its free end (i.e., remote from pivot 5), arm 19 supports a pivot 20 upon which is rockably mounted a feed bellcrank 21, which has two arms 35, 36. Arm 35, sinuous in contour, has a slot 37 which controls movement of feed bellcrank 21 during the latters operation by reason of cooperation with a projecting stud 41 fixed to flange 2a oflift bracket 3. Arm 36 of drive bellcrank 21 terminates in pawl 38, previously mentioned.

The lift actions of bellcrank 18 which result in a corresponding ribbon drive action through bellcrank 21 will next be described (still using cartridge 1 for reference). Considering now a complete operational cycle, power roll shaft 34 and gear 33 engagingly, but laterally movably mounted upon shaft 34 are driven one revolution clockwise (a direction chosen merely for purposes of this description because such direction is arbitrary in view of symmetry of camming slot 30). Gear 32 having a diameter exactly twice the diameter of gear 33, each clockwise revolution (one cycle) of gear 33 therefore rotates gear 32 counterclockwise one-half revolutionnThe first quarter-revolution, say, of gear 32 (a half-cycle of gear 33) displaces cam roller 29 from its dwell 54a to a first cam lobe 43, this lobe 43 being the higher one of two lobes 43, 44 in camming slot 30, both these lobes 43, 44 including a constant radius portion at their peaks so that ribbon 8 may be held still during printing, in known fashion. Consequently, as bail 26 pivots clockwise about stud 27, lift bellcrank 18 pivots counterclockwise about stud 5, and cartridge 1 is urged counterclockwise by cooperation with ears 39, on arms 22, 19, thereby bringing ribbon portion 8a to its uppermost position (corresponding to the peak of lobe 43), such that the character font of print element 42 selected by the key button depressed will contact the lower half of the active ribbon portion 8a and record the selected character on record medium 14,as print element 42 proceeds through a print cycle in known fashion.

Simultaneously, ribbon feed bellcrank 21 being pivotally mounted about stud 20 fixed to arm 19 of bellcrank 18, and having its pivoting motion further controlled by cooperation between camming slot 37 in its arm 35 and stud 41 fixed to bracket 3, also pivots counterclockwise, preparatory to a feeding engagement between pawl 38 and the next tooth 50a of ratchet 53. Camming slot 37 is shaped such as to aid in limiting the travel of pawl 38 to an amount sufficient to pick up just the one tooth 50a. In FIG. 2b, it will be noted that during counterclockwise rotation of bellcrank 21, the furthest retracted position of pawl 38 (shown by a dotted outline) is shifted to the left that is, behind the next tooth 50a of ratchet 53. This is accomplished through use of a resilient material (such as an acetal plastic) for bellcrank 21 or by providing stud 20 with a head portion and urging bellcrank 21 leftward in known fashion by means of Belleville springs (not shown) inserted between the bellcrank 21 and the head of stud 20.

In the second quarter-revolution of gear 32, say, the reverse sequence occurs in that cam roll 29 traverses from lobe 43 to cam dwell 54b equal in height to cam dwell 54a, resulting in return of ribbon cartridge 1 to its normal position in which the printed line on record medium 14 is visible. During this second half of the cycle, ribbon feed bellcrank 21 now rotates clockwise about pivot 20 causing pawl 38 to engage tooth 50a of ratchet 53, pawl 38 having fallen behind tooth 50a during the first half of the cycle, it will be recalled. Thus, feed gear 11 is rotated counterclockwise, in mesh with driven feed gear 12.

Because the cartridge 1 has ribbon 8 prethreaded between feed gears 11 and 12, then during rotation of these gears 11, 12, meshing ones of their respective gear teeth 17a, 17b contact ribbon 8, the different number of teeth 17a, 17b reducing the tendency of ribbon 8 to stick to gears l1, 12. Note that if the gears 11, 12 are identical, the teeth 17a, 17b then induce therein an equally spaced, vertical creasing which facilitates entry into chamber 7 in a more condensed fashion, resulting in a greater volume of ribbon 8 being storable in a cartridge 1 of given size. Rotation of these gears 11, 12 also moves ribbon 8 across the span between supports 13a, 13b to place fresh ribbon 8 in front of print element 42, as previously described.

On the following selection of a key button, another clockwise revolution (one cycle) of gear 33 causes the second half-revolution of gear 32. In this second halfrevolution, cam roller 29 starts at dwell 54b; progresses to the highest portion of lobe 44, which has a rise smaller than that of lobe 43; and then returns to dwell 54a, the original starting point in the foregoing description. The actions during this second cycle are similar to those described for the first cycle, except that the smaller rise of lobe 44 moves lift bellcrank 18 through a smaller arc and thus rocks cartridge 1 a correspondingly small amount so that the selected character font of print element 42 now contacts the upper portion of ribbon 8 during the print action by element 42. The alternating upper and lower impressions on the ribbon 8 result in a more economical ribbon usage. It should also be remarked that the design of the drive mechanism may be made such that a ribbon motion of half a character space occurs in each cycle (which would result in staggered arrangements of the letters I-I marked on the ribbon of FIG. 2a), or such that a ribbon motion of a full character space occurs only after two impressions have been made on record medium 14, that is, only in every other cycle of gear 33 (resulting in the aligned arrangement of the letters H not illustrated in FIG. 2a). The latter type of feed motion could be achieved, for instance, by choosing dimensions of the respective bellcranks 18, 21 and the shape of slot 37 such that the second movement of bellcrank 18 would be insufficient to bring pawl 38 behind tooth 50a.

Between impression cycles, the power roll clutch is disengaged, of course, rendering power roll shaft 34 and lift and feed bellcranks 18, 21 stationary until another character imprint is desired, at which time the above-described operational sequence is repeated upon depression of a further keybutton.

The above description discloses a novel spoolless ribbon cartridge 1 or 61 and a combined ribbon lift and feed mechanism therefor, adaptable to business machines, comprising a cartridge 1 or 61 storing a supply of endless fabric ribbon 8 or a roll of carbon ribbon 66, respectively, and having built-in ribbon supports 13a, 13b over which the ribbon 8 or 66 passes to built-in ribbon feed members 11, 12, 53 which crease the ribbon 8 or 66 while returning it to the cartridge 1 or 61 for storage therein in folded fashion, and which cooperate with a combined ribbon lift and ribbon feed drive mechanism 18, 21, 26, 29, 30 on the machine, that mechanism being operated by the shaft 34 driven by the usual powersource.

In light of the above-described embodiments, it will be evident to those skilled in the art that the present invention is susceptible of other modifications, substitutions, etc. and such are intended to be within the scope of the invention, it being defined only by the appended claims.

We claim:

1. In a printing machine of the type having a cartridge for a ribbon, at least one projecting member on the cartridge, means for pivotally mounting the cartridge, and means for oscillating the cartridge about the pivotal mounting means, wherein the improvement comprises, in combination:

a. first and second feed rotors journaled in the projecting member of the cartridge to feed the ribbon between the first and second feed rotors;

b. a ratchet connected to the first feed rotor; and

c. a pawl actuated by the oscillating means to engage the ratchet to rotate the first feed rotor and feed the ribbon during oscillation of the cartridge.

2. In a printing machine of the type having:

1. at least one print element;

2. means for mounting a ribbon in the printing machine, the ribbon mounting means having projecting members to hold a portion of the ribbon between the projecting members;

3. a first bell crank pivotally mounted in the printing machine and engaging the ribbon mounting means;

4. a cam follower;

5. means for connecting the cam follower to the first bell crank;

6. means for imparting motion;

7. a cam connected to the motion imparting means and engaged by the cam follower to oscillate the projecting members to move the portion of the ribbon held by the projecting members from a home position to a print position for impact by the print element to print on a record medium; and

8. a rotor in contact with the ribbon; wherein the improvement comprises:

a second bell crank having a cam arm and a pawl arm and pivotally connected to the first bell crank, the cam arm of the second bell crank having a cam slot engaging a stud in the printing machine and the pawl arm of the second bell crank positioned to engage the rotor to feed the ribbon during oscillation of the projecting members.

3. The printing machine of claim 2, in which the ribbon mounting means is a cartridge and the rotor is a first gear, and further comprising:

a. means for pivotally mounting the cartridge in the printing machine;

b. a second gear in the cartridge sandwiching the ribbon between the first and second gears; and

c. a ratchet connected to the first gear, the pawl arm of the second bell crank engaging the ratchet.

4. The combination of claim 3, wherein said ratchet is normally held stationary by a detent on said cartridge and further including a resilient member on said cartridge clamping said ribbon to one of said projecting members.

5. The combination of claim 4, wherein said detent and said projecting members are integral parts of said cartridge, and wherein said first and second gears have a respectively different number of teeth. 

1. at least one print element;
 1. In a printing machine of the type having a cartridge for a ribbon, at least one projecting member on the cartridge, means for pivotally mounting the cartridge, and means for oscillating the cartridge about the pivotal mounting means, wherein the improvement comprises, in combination: a. first and second feed rotors journaled in the projecting member of the cartridge to feed the ribbon between the first and second feed rotors; b. a ratchet connected to the first feed rotor; and c. a pawl actuated by the oscillating means to engage the ratchet to rotate the first feed rotor and feed the ribbon during oscillation of the cartridge.
 2. In a printing machine of the type having:
 1. at least one print element;
 2. means for mounting a ribbon in the printing machine, the ribbon mounting means having projecting members to hold a portion of the ribbon between the projecting members;
 3. a first bell crank pivotally mounted in the printing machine and engaging the ribbon mounting means;
 4. a cam follower;
 5. means for connecting the cam follower to the first bell crank;
 6. means for imparting motion;
 7. a cam connected to the motion imparting means and engaged by the cam follower to oscillate the projecting members to move the portion of the ribbon held by the projecting members from a home position to a print position for impact by the print element to print on a record medium; and
 8. a rotor in contact with the ribbon; wherein the improvement comprises: a second bell crank having a cam arm and a pawl arm and pivotally connected to the first bell crank, the cam arm of the second bell crank having a cam slot engaging a stud in the printing machine and the pawl arm of the second bell crank positioned to engage the rotor to feed the ribbon during oscillation of the projecting members.
 3. The printing machine of claim 2, in which the ribbon mounting means is a cartridge and the rotor is a first gear, and further comprising: a. means for pivotally mounting the cartridge in the printing machine; b. a second gear in the cartridge sandwiching the ribbon between the first and second gears; and c. a ratchet connected to the first gear, the pawl arm of the second bell crank engaging the ratchet.
 3. a first bell crank pivotally mounted in the printing machine and engaging the ribbon mounting means;
 4. a cam follower;
 4. The combination of claim 3, wherein said ratchet is normally held stationary by a detent on said cartridge and further including a resilient member on said cartridge clamping said ribbon to one of said projecting members.
 5. means for connecting the cam follower to the first bell crank;
 5. The combination of claim 4, wherein said detent and said projecting members are integral parts of said cartridge, and wherein said first and second gears have a respectively different number of teeth.
 6. means for imparting motion;
 7. a cam connected to the motion imparting means and engaged by the cam follower to oscillate the projecting members to move the portion of the ribbon held by the projecting members from a home position to a print position for impact by the print element to print on a record medium; and
 8. a rotor in contact with the ribbon; wherein the improvement comprises: a second bell crank having a cam arm and a pawl arm and pivotally connected to the first bell crank, the cam arm of the second bell crank having a cam slot engaging a stud in the printing machine and the pawl arm of the second bell crank positioned to engage the rotor to feed the ribbon during oscillation of the projecting members. 